Well yes and no. Our proposal wasn't to keep tabs on cars. There's no tracking whatsoever. Lights have no idea of knowing where you have been or who you are:

Well yes and no. Our proposal wasn't to keep tabs on cars. There's no tracking whatsoever. Lights have no idea of knowing where you have been or who you are: you're just telling them how much pain you've been suffering in the near past. The tokens aren't marked -- they're simply currency so to speak. The approach does require two-way communication between cars and nearby traffic lights. But the approaches that various people are suggesting, including this article, largely rely on communication as well: just one-way. The lights generally need to be able to detect cars approaching and at quite a distance. This requires the cars announcing their presence: either the lights have a sophisticated sensor system (lots of plates in the road, or a vision system) or -- more likely -- the cars need to have beacons installed which let the lights know they're coming. A great many of these methods also benefit from knowing not only that cars are approaching but where they intend to go -- are they going to turn left or right or straight -- well before they get into their lanes. This requires additional signaling. What Gabriel Balan picked up on, is that to make the system fairer and more efficient, you need to be able to transfer historical information from light to light. Not only information about how many cars are coming, but what their previous histories were. If you don't want the lights communicating with one another -- essentially tracking your car -- you can do what he did: have the cars build up a history on their own and relay that to the lights as they approach them.